在使用自定义ListView视图时，经常会采用重用ListView中视图的方式来提高滑动和显示效率，但是随之而来的一个问题是listview中数据经常显示混乱。

通常情况下，我们重写的方法是这样的：

inflater = LayoutInflater.from(context);

@Override

  public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder holder;

    if (convertView == null) {

      convertView = inflater.inflate(R.layout.book_item, null);

      holder = new ViewHolder(convertView);

      Book book = books.get(position);

      holder.bookName.setText(book.getName());

      holder.bookTime.setText(book.getTime());

      convertView.setTag(holder);

    } else {

      holder = (ViewHolder) convertView.getTag();

    }

    return convertView;

  }

  class ViewHolder {

    ImageView bookPic;

    TextView bookName;

    TextView bookTime;

    public ViewHolder(View view) {

      bookPic = (ImageView) view.findViewById(R.id.iv_book_pic);

      bookName = (TextView) view.findViewById(R.id.tv_book_name);

      bookTime = (TextView) view.findViewById(R.id.tv_book_time);

    }

  }

这样通常会造成list显示混乱，是因为当我们重用视图但是convertView != null的时候我们并没有去重新加载数据，写成下面这种形式就会重新加载数据了：

@Override

  public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder holder;

    if (convertView == null) {

      convertView = inflater.inflate(R.layout.book_item, null);

      holder = new ViewHolder(convertView);

      convertView.setTag(holder);

    } else {

      holder = (ViewHolder) convertView.getTag();

    }

    Book book = books.get(position);//不管视图是否重用，都重新设置数据

    holder.bookName.setText(book.getName());

    holder.bookTime.setText(book.getTime());

    return convertView;

  }